Tar sands mining process

ABSTRACT

A process wherein tar sands are mined through optimum utilization of solids movement for the ecological control of land reclamation during and for optimum tar sands mining operations.

United States Patent [191 Hendry 4] TAR SANDS MINING PROCESS [75] Inventor: Robert D. Hendry, Edmonton,

Alberta, Canada [73] Assignees: Canada-Cities Service Ltd.; Imperial Oil Limited; Atlantic Richfield Canada Ltd.; Gulf Oil Canada Limited, part interest to each [22] Filed: Feb. 18, 1972 [21] Appl. No.: 227,396

[52] US. Cl 299/7, 61/35, 299/18, 299/19 [51] Int. Cl. E21c 41/10 [58] Field of Search 299/18, 19, 7; 61/35 Mar. 26, 1974 [56] References Cited UNITED STATES PATENTS 878,575 2/1908 Stevenson et al 299/7 1,996,771 4/1935 Macready 299/7 Primary Examiner--Ernest R. Purser Attorney, Agent, or Firm--E. Peter Johnson 5 7] ABSTRACT A process wherein tar sands are mined through optimum utilization of solids movement for the ecological control of land reclamation during and for optimum tar sands mining operations.

6 Claims, 2 Drawing Figures PATENTEI] HAR 2 6 I974 sum 1 or z TAR SANDS MINING PROCESS BACKGROUND OF THE INVENTION The present invention relates to land reclamation during tar sands mining operations. More particularly, the present invention is a process wherein the overburden removed from tar sands deposits and the sand tailings produced from extraction of bitumen from the tar sands are optimally recovered and utilized for land reclamation.

Most tar sand mining operations involve strip mining preocedures wherein a drag line, for example, a walking drag line derrick form of apparatus, is utilized to strip the overburden from a tar sand deposit with subse quent accumulation of the tar sands at ancillary positions. Bucket wheel reclaimers are utilized in conjunction with moveable conveyorsto transfer the tar sands into feed trains or other conveying devices for the' movement of the tar sand materials to an extraction plant for the separation of bitumen from the tar sands. In general, the tar sand mining operation involves very little thought as to land reclamation prior to the operation. Generally, the overburden is stripped from the tar sand deposit and continually utilized to fill a previously mined tar sand pocket.

The conventional drag line mining operations leave considerably larger areas of debris and overburden material about the mining operation than is desirable for land reclamation. This fact is principally due to the fact that the volume of tailings sand left after processing is much greater than the tightly compacted tar sand material originally minedand, therefore, will generally overflow the mining area and must be left in sludge ponds or other previously formed areas for disposal, causing considerable expense to be incurred to reclaim the site of the mining operation. What is required is a process for the miningof tar sands wherein optimal utilization of the previously mined area for tailing sands and overburden disposal may be obtained.

It isan object of the present invention to provide a processfor tar sands mining operations. It is a: further object of the present invention to provide a process wherein optimum mining and utilization of overburden andtailing sands may be utilized in the tar sands mining operation.

With these and other objects in mind, the present invention may be more readily understood by referral to the accompanying drawings and following discussion.

SUMMARY OF THE INVENTION The objects of the present invention are accomplished through a process for mining tar sands where overburden is stripped from the tar sands deposit, the tar sands are removed from the deposit, and processed into bitumen and tailing sand. The improvement in the process of the present invention comprises removing the overburden from the portion of the tar sands deposits to be initially mined and placing the removed overburden mined in the initial sequence of the operation about the portion of an area to be immediately mined to form a dike. The overburden subsequently mined is returned to the next preceding area mined with subsequent depositing of processed tailing sands upon the overburden deposit, at least until a ground level is maintained, subsequent to which the dike is positioned upon the tailing sands deposited. The steps of the mining procedure are repeated until the tar sands deposit is fully developed. In general, it is preferred that the overburden tar sands be removed in rows, that the overburden be returned and the tailing sands deposited within the mined area and with replacement of the dike of overburden about the mined area and subsequent mining-of the area under the removed overburden dike.

BRIEF DESCRIPTION OF THE DRAWINGS DETAILED DESCRIPTION OF THE INVENTION As disclosed, the process of the: present invention is a mining operation sequence wherein overburden is initially removed from a tar sands deposit and positioned about the section to be mined to form a dike. Subsequent removal of tar sands from the deposit for processing and recovery of bitumen from the tar sands is then accomplished. Stripped overburden removed from the tops of the tar sands deposit is deposited upon the stripped tar sands beds. Tailing sands are then deposited to ground height with the overburden surrounding the mined area forming a dike in order to provide a confined area for depositing of the voluminous tailings sand produced in conjunction with the tar sands mining project. The process readily provides easily reclaimed land structures for ecological development of the tar sands deposit.

The particular utilization of the process of the present'invention may be more readily understood by referral to the accompanying Figures. FIG. 1 depicts a drag line mining operation after several years of mining operation utilizing the process of the present invention. The initial overburden piles have been removed by a walking drag line apparatus 12 and deposited to form an overburden wall 4 about the area to be subsequently mined 16. Tar sands are removed and deposited in tar sand piles 18 for recovery by a bucket wheel reclaimer 20 which may be positioned so as to feed a moving conveyer 22 which dumps to one or more electric trains 24 utilized to haul the tar sands to an extraction plant 26 for the separation of bitumen from the tar sands material and the by-product of tailing sands. Subsequent to the initial removal of overburden and the definition of the mining area, through the formation of overburden walls 4, overburden removed is redeposited in the initial tar sands bed in strips to form overburden piles 28 with a sequence of overburden removal deposited upon already mined tar sands areas and subsequent tar sand removal from the recently stripped deposit occurring. Sand tailings are then'deposited on top of the overburden piles to the height above ground level within the confines of the overburden walls 4. A preferred embodiment of the invention as shown in FIG. 2 involves filling in the mined area with overburden and sand tailings only to ground height and then shifting the overburden walls 4 back onto the deposited tailings around the outer edge of the mined area as shown at 14 before filling in the mined area to above ground level. In this way valuable tar sand deposits may be mined rather than permanently buried under the overburden walls 4. A floating pump station 30 is provided such that tailing sands 32 contained either in solids or slurry form are deposited through dump stations or pumping stations onto the'overburden piles 28 remaining after tar sand removal. The process allows disposal of the greater volume of the tailing sands 32 formed by the extraction process, this volume generally being to 25 percent in excess of the volume of the denser material tar sands removed from the open mine pit. The greater volume of tailings sands formed may be readily accounted for within the dike as moved upon the tailings sands filled to ground level, leaving the area exposed for current mining operations.

As depicted, it is preferred to utilize the row form of open pit mining operation as it conveniently allows the utilization of'one or more walking drag lines and subsequently utilized bucket wheel claimers, conveyors and trains for the total mining operation. The exact utilization of the process of the present invention is subject to the individual constraints of the terrain upon which the mining operation is practiced and the economic variables of the extraction plant and distances involved and modifications may be made without departing from the spirit and scope of the invention.

Therefore, I claim:

1. In a process for the mining of tar sands overlaid by overburden, the improvement which comprises:

a. removing the overburden from a portion of the tar sand deposit to be mined; I

b. positioning the overburden removed in step (a) about a section of the area to be immediately mined to form a dike;

c. mining exposed tar sands from the section and processing it into bitumen and tailings sand;

d. removing overburden from another portion of the tar sands deposit and returning it to the next preceding area mined; and

e. depositing processed tailings sand upon an overburden depositpreviously formed.

2. The process of claim 1 wherein the overburden and tar sands are removed in rows.

3. The process of claim 2 wherein the overburden is returned and the tailings sand is deposited within the mined area to the height of the overburden positioned about the mined area.

4. The process of claim 1 further comprising depositing the processed tailings sands upon the overburden deposits until the sands reach ground level and moving the overburden formed into the dike onto the outer edge of the mined area upon the deposited tailings sands.

5. The process of claim 4 wherein the overburden and tar sands are removed in rows.

6. The process of claim 5 wherein the overburden is returned and the tailings sand is deposited within the mined area to the height of the overburden positioned about the mined area. 

1. In a process for the mining of tar sands overlaid by overburden, the improvement which comprises: a. removing the overburden from a portion of the tar sand deposit to be mined; b. positioning the overburden removed in step (a) about a section of the area to be immediately mined to form a dike; c. mining exposed tar sands from the section and processing it into bitumen and tailings sand; d. removing overburden from another portion of the tar sands deposit and returning it to the next preceding area mined; and e. depositing processed tailings sand upon an overburden deposit previously formed.
 2. The process of claim 1 wherein the overburden and tar sands are removed in rows.
 3. The process of claim 2 wherein the overburden is returned and the tailings sand is deposited within the mined area to the height of the overburden positioned about the mined area.
 4. The process of claim 1 further comprising depositing the processed tailings sands upon the overburden deposits until the sands reach ground level and moving the overburden formed into the dike onto the outer edge of the mined area upon the deposited tailings sands.
 5. The process of claim 4 wherein the overburden and tar sands are removed in rows.
 6. The process of claim 5 wherein the overburden is returned and the tailings sand is deposited within the mined area to the height of the overburden positioned about the mined area. 